I'm not very confident with Math ematica. I'm learning now for College purpose...
Anyway, I think it's a little bug in your code. Let's explain... When you define
f[x_]+g[x_]^:=1, you are saying to mathematica that when it find f[x_]+g[x_], it must
replace it with 1. so the derivatives of a costant is zero.
I think so. If I'm wrong, let me know.
ciao
sabbri
From: "Sunil Pinnamaneni" <PINNAMA at CIMS.NYU.EDU>
To: mathgroup at smc.vnet.net
To: mathgroup at smc.vnet.net
Subject: [mg46023] [mg46014] Simple Differentiation?
Date: Mon, 2 Feb 2004 05:21:28 -0500 (EST)
In Mathematica 5.0, if one types in:
f[x_]+g[x_]^:=1 (1)
and then types
dx(f[x]+g[x])
we get 0.
However, if we type dx(f[x]) + dx(g[x]) after typing (1), we get
f'[x] + g'[x].
Mathematica doesn't recognize that f'[x]+g'[x]=
dx(f[x]+g[x]), which equals 0. How does one get Mathematica to do this?
I'm interested in more complicated examples, which involve more complex
differential relations, but I should be able to do things in those
situations given a nice, natural way of handling this toy case. Though this
seems like a pretty simple thing, I wasn't able to find any thing in the
Mathematica Book or elsewhere, which would help with this type of things.
Thanks,
Sunil